The present invention relates to computer systems and other devices having keyboards and more particularly to keyboards. Even more particularly, the present invention relates to a simpler and more cost-effective way of designing and producing the keys on such keyboards.
As is well-known, in various devices including personal computers (PC) and electronic desk calculators, a keyboard to be operated by a user is constructed so that each of a plurality of keys is capable of movement through an upstroke/downstroke (hereinafter referred to as xe2x80x9cup/down movementxe2x80x9d in this specification). The functions required of such keys include, in addition to a function of allowing the key top to move up and down, a function of operating a switch provided on a circuit board at a position below each key, and a function of returning the key top to the home position after allowing the key top to be depressed, and also include, as a function for enabling a user to feel improved key response when operating the key, a function of stopping the key from shifting in any direction other than the vertical direction when the key top moves up and down.
FIG. 6 shows an example of a known structure of a key having such functions. In FIG. 6 are illustrated a key top 1 forming a key face, reference numeral 2 denotes an up/down mechanism which supports the key top 1 so that the key top 1 can move up and down, and reference numeral 3 denotes a rubber dome for returning the key top to the home position.
The up/down mechanism 2 is constituted by a pair of arms 4 and 5, a top plate 6, and a fixing member 7. In this up/down mechanism 2, the arms 4 and 5 are rotatably connected to each other by a shaft 4a so as to operate as a pantograph or scissor, thereby enabling movement in the up/down direction. The top plate 6 is rotatably connected at its one end to the arm 4 and slidably engages with the arm 5 at the other. The top plate 6 has a function of operating as an element for reinforcing the arms 4 and 5 when the arms 4 and 5 expand or contract, and a function of receiving the top end of the rubber dome 3. The fixing member 7 slidably fixes the lower ends of the arms 4 and 5 on an unillustrated base plate.
The rubber dome 3 is made of an elastic material, which is a kind of rubber or the like. The rubber dome 3 is placed inside the up/down mechanism 2 and its top end is brought into abutment against the lower surface of the top plate 6 of the up/down mechanism 2. A downwardly-projecting projection is provided on the reverse side of the top end of the rubber dome 3 to operate a switch in a membrane sheet (circuit board) provided on the unillustrated base plate.
In the thus-constructed key, when a user depresses the key top 1, the up/down mechanism 2 operates so as to contract. The rubber dome 3 is thereby compressed and deformed to move its top end downward. With the downward movement of the top end, the unillustrated projection provided on the reverse side of the top end presses the switch, thereby enabling the key top 1 operation to be detected.
The compressed and deformed rubber dome 3 has a force for restoring its original shape. When the user stops pressing the key top 1 downward, the top plate 6 is moved upward by the restoring force of the rubber dome 3 to expand the up/down mechanism 2, thereby returning the key top 1 to the home position.
There are problems associated with a key having the above-described construction in that the structure of the up/down mechanism 2 is particularly complicated and the parts cost and assembly cost are therefore high. As is well-known, a keyboard has a plurality of keys, assembly of the parts of each key is time-consuming, and the total number of parts is considerably large. Therefore it is important to solve the above-described problem.
The number of parts of the up/down mechanism 2 may, of course, be reduced in any number of ways. From the viewpoint of maintaining the desired stability of the key during up/down movement, however, it must be said that it is difficult to reduce the number of parts without sacrificing other desirable characteristics of the keyxe2x80x94such as stability, feel, consistency, etc. Therefor, it is an object of the present invention to provide kays on a keyboard which provide a user with the desired feel and stability of current keyboards but which may be produced using fewer parts and at a lower cost.
The inventors of the present invention have studied eagerly with this object and found it effective to form a plurality of keys as one integral component. However, problems described below arise in a case where a plurality of keys are formed as one integral component.
As shown in FIG. 5(a), in a case where keys are formed by combining a key member 11 and a cover 12, a plurality of (e.g., two) key tops 11a formed on the key member 11 so as to project upward therefrom are fitted in holes 12a formed in the cover 12.
Ordinarily, the above-described key member 11 and cover 12 are provided as molded resin components. Any combination of a plurality of components, including such molded resin components, entails a problem relating to a working error.
A predetermined tolerance is given on each of the distance P1 between key tops 11a and the distance P2 between the holes 12a determined at the time of resin molding. For example, in a case where a row of a plurality of keys is formed such that each of the distances P1 and P2 between the keys placed at the opposite ends exceeds 100 mm, a tolerance of typically xc2x10.25 mm exists. In this case, if the distance P1 of the resin molded key member 11 includes a working error of xe2x88x920.25 mm and if the distance P2 of the cover 12 includes a working error of +0.25 mm, a total error of 0.50 mm exists between the two distances.
Then, when the key top 11a of the key member 11 is fitted around the hole 12a of the cover 12 shown in FIG. 5(b), the center of the key top 11a is out of alignment with the center of the hole 12a, even though each of the key member 11 and the cover 12 has the accuracy within the tolerance.
If such a misalignment exists, interference may occur between the key top 11a and the hole 12a to impede the up/down movement of the key top 11a. To avoid this interference, a clearance is set between the outside diameter of the key top 11a and the inside diameter of the hole 12a by factoring in an error within the above-described tolerance.
However, a state where the amount of misalignment of the key top 11a with the hole 12a in one direction is so large that a portion of the gap 13 around the key cap 11a narrows or disappears, as shown in FIG. 5(b), is undesirable in terms of appearance. For this reason, the clearance may be increased to ensure that the gap 13 is continuously formed along the entire perimeter of the key top 11a. From the keys with an increased clearance, however, a user may have the impression that the working accuracy of the entire PC is low. Also, the possibility of foreign objects or the like entering through the gap 13 is increased.
The above-described problems become more serious if the number of keys continuously arranged to form one integral component is increased or if the length of the integral component is increased.
The above-described problems can of course be solved if the working error at the time of molding of each of the key member 11 and the cover 12 is reduced. However, this is not an effective solution of the problems since use of means for reducing the working error of the molded resin components leads directly to a considerable increase in mold cost.
A computer system in accordance with the present invention provided by considering the above-described problems has a keyboard of a construction in which a plurality of keys arranged in a continuous row at least in one direction are supported on a frame having an adjustment portion for enabling adjustment of the position of each of the plurality of keys in the above-mentioned direction. Preferably, the plurality of keys are integrally supported on the frame.
The adjustment portion may be of any construction if it enables adjustment of the position of each of the keys supported on the frame. A deformable portion which is a portion of the frame deformable in the lengthwise direction of the frame may be provided as the adjustment portion. The frame is deformed in the lengthwise direction to adjust the pitch (interval) of the keys supported on the frame. Thus, in the structure in which the plurality of keys are supported on the frame, the position of each key can be adjusted to absorb working errors of the components.
An arrangement is conceivable in which an up/down mechanism, e.g., the mechanism 2 shown in FIG. 6 is used as a mechanism for enabling keys to move up and down and is supported on a frame. However, from the viewpoint of the object of reducing the number of parts by integrally combining a plurality of parts in accordance with the present invention, it is preferred that the frame itself have a mechanism for enabling the keys to move up and down. That is, elastically deformable arms extending from the frame are formed and the keys are provided on the arms. In this case, the keys may be formed integrally with the arms or may be provided as separate parts to be attached to the arms.
If a cover member which can close space between the plurality of keys are provided on the keyboard, it is preferable to form positioning portions such as pins for positioning the keys supported on the frame. The frame on which the keys are supported is corrected by the positioning portions to adjust the positions of the keys.
The present invention can also be grasped as a device not limited to the computer system. This device is characterized by including a plurality of keys, a frame extending in a direction corresponding to the direction of arrangement of the plurality of keys in a continuous row, and arms extending from the frame and capable of enabling the plurality of keys to move up and down. In the device thus constructed, the number of parts constituting the keys can be limited to the smallest possible number.
The frame is provided on both sides of the continuous row of the plurality of keys arranged in one direction. Curved/bent portions curved or bent laterally may be provided on the frame. The curved/bent portions are provided for adjustment of the pitch of the plurality of keys.
The present invention can also be grasped as a keyboard having a plurality of keys. This keyboard is characterized by including a frame provided with adjustment portions for adjusting the spacing between the plurality of keys and positioning portions for positioning the keys on a base of the keyboard.
This keyboard may also have a cover member which closes space between the plurality of keys. Preferably, positioning pins for positioning the positioning portions on the base are provided on the cover member. While the spacing between the keys is adjusted by the adjustment portion, the keys are positioned and fixed by the positioning portions. It may otherwise be said that the keys are positioned on the cover member, but the positioning in this expression is essentially the same as positioning of the positioning portions on the base since both the keys and cover member are mounted on the base.
In this case, the plurality of keys are not always arranged in a continuous row in one direction. For example, the present invention may be applied to an arrangement in which keys are alternately placed on opposite sides of a line, i.e., a staggered key layout.
A keyboard in another aspect of the present invention has a frame on which a plurality of keys arranged in one direction are supported so as to be able to move up and down, and which is provided with a deformable portion capable of deforming along the direction of arrangement of the plurality of keys and holes provided on opposite sides of the deformable portion. This keyboard also has a cover having openings through which the plurality of keys are exposed, the cover also having pins which are passed through the holes of the frame to be fixed on a base. If the frame and the cover have variations in size due to working errors or temperatures, the frame is fixed while absorbing the errors in such a manner that the pins of the cover are passed through the holes provided on the opposite sides of the deformable portion of the frame and are fixed on the base.
A key member constituting the keyboard of the present invention is characterized by including a pair of side support portions, a plurality of key tops placed between the pair of side support portions, and arms each having its one end connected to one of the key tops and the other end connected to one of the side support portions, each arm being elastically deformable. In this arrangement, when one of the key tops is pressed, the arms are elastically deformed to realize stroke movement of the key.
If a curved/bent portion is formed on each side support portion between each adjacent pair of said key top, the pitch of the keys can be adjusted.
Preferably, the arms extend from the corresponding one of the key tops toward the pair of side support portions so as to have a shape similar to the shape of the letter V, and the next key top is located between these arms extending generally in the form of V. In this manner, the length of the arms is maximized.
In other words, the other ends of the arms are connected to the side support portions in the vicinity of the next key top adjacent to the key top to which the one ends of the arms are connected.
This arrangement, in which each pair of arms are respectively joined to the side frames on opposite sides of the row of the plurality of keys, is not exclusively used. For example, another arrangement is possible in which a pair of arms extending from each key top are joined only to one of the frames located on opposite sides of the row of the plurality of keys.
Preferably, each of the above-described arms is formed so that its sectional area is smaller at the other end on the side support portion side than at the one end, whereby deformation of the arm when the key top is pressed for a key operation is concentrated in a portion closer to the other end. In contrast, in an arm without such a change in sectional area, deformation of the arm is generally uniform through the entire length of the arm. In comparison between these types of arms, while the inclination of the key top surface on the one end of the arm without a change in sectional area is large, the inclination of the key top surface can be reduced in the case of the above-described arm in which deformation is concentrated at a position closer to the other end.